1 /*- 2 * Copyright (c) 2010 The FreeBSD Foundation 3 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net> 4 * All rights reserved. 5 * 6 * This software was developed by Pawel Jakub Dawidek under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/disk.h> 36 #include <sys/ioctl.h> 37 #include <sys/jail.h> 38 #include <sys/stat.h> 39 #ifdef HAVE_CAPSICUM 40 #include <sys/capsicum.h> 41 #include <geom/gate/g_gate.h> 42 #endif 43 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <pwd.h> 47 #include <stdarg.h> 48 #include <stdbool.h> 49 #include <stdio.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 #include <pjdlog.h> 54 55 #include "hast.h" 56 #include "subr.h" 57 58 int 59 vsnprlcat(char *str, size_t size, const char *fmt, va_list ap) 60 { 61 size_t len; 62 63 len = strlen(str); 64 return (vsnprintf(str + len, size - len, fmt, ap)); 65 } 66 67 int 68 snprlcat(char *str, size_t size, const char *fmt, ...) 69 { 70 va_list ap; 71 int result; 72 73 va_start(ap, fmt); 74 result = vsnprlcat(str, size, fmt, ap); 75 va_end(ap); 76 return (result); 77 } 78 79 int 80 provinfo(struct hast_resource *res, bool dowrite) 81 { 82 struct stat sb; 83 84 PJDLOG_ASSERT(res->hr_localpath != NULL && 85 res->hr_localpath[0] != '\0'); 86 87 if (res->hr_localfd == -1) { 88 res->hr_localfd = open(res->hr_localpath, 89 dowrite ? O_RDWR : O_RDONLY); 90 if (res->hr_localfd == -1) { 91 pjdlog_errno(LOG_ERR, "Unable to open %s", 92 res->hr_localpath); 93 return (-1); 94 } 95 } 96 if (fstat(res->hr_localfd, &sb) == -1) { 97 pjdlog_errno(LOG_ERR, "Unable to stat %s", res->hr_localpath); 98 return (-1); 99 } 100 if (S_ISCHR(sb.st_mode)) { 101 /* 102 * If this is character device, it is most likely GEOM provider. 103 */ 104 if (ioctl(res->hr_localfd, DIOCGMEDIASIZE, 105 &res->hr_local_mediasize) == -1) { 106 pjdlog_errno(LOG_ERR, 107 "Unable obtain provider %s mediasize", 108 res->hr_localpath); 109 return (-1); 110 } 111 if (ioctl(res->hr_localfd, DIOCGSECTORSIZE, 112 &res->hr_local_sectorsize) == -1) { 113 pjdlog_errno(LOG_ERR, 114 "Unable obtain provider %s sectorsize", 115 res->hr_localpath); 116 return (-1); 117 } 118 } else if (S_ISREG(sb.st_mode)) { 119 /* 120 * We also support regular files for which we hardcode 121 * sector size of 512 bytes. 122 */ 123 res->hr_local_mediasize = sb.st_size; 124 res->hr_local_sectorsize = 512; 125 } else { 126 /* 127 * We support no other file types. 128 */ 129 pjdlog_error("%s is neither GEOM provider nor regular file.", 130 res->hr_localpath); 131 errno = EFTYPE; 132 return (-1); 133 } 134 return (0); 135 } 136 137 const char * 138 role2str(int role) 139 { 140 141 switch (role) { 142 case HAST_ROLE_INIT: 143 return ("init"); 144 case HAST_ROLE_PRIMARY: 145 return ("primary"); 146 case HAST_ROLE_SECONDARY: 147 return ("secondary"); 148 } 149 return ("unknown"); 150 } 151 152 int 153 drop_privs(const struct hast_resource *res) 154 { 155 char jailhost[sizeof(res->hr_name) * 2]; 156 struct jail jailst; 157 struct passwd *pw; 158 uid_t ruid, euid, suid; 159 gid_t rgid, egid, sgid; 160 gid_t gidset[1]; 161 bool capsicum, jailed; 162 163 /* 164 * According to getpwnam(3) we have to clear errno before calling the 165 * function to be able to distinguish between an error and missing 166 * entry (with is not treated as error by getpwnam(3)). 167 */ 168 errno = 0; 169 pw = getpwnam(HAST_USER); 170 if (pw == NULL) { 171 if (errno != 0) { 172 pjdlog_errno(LOG_ERR, 173 "Unable to find info about '%s' user", HAST_USER); 174 return (-1); 175 } else { 176 pjdlog_error("'%s' user doesn't exist.", HAST_USER); 177 errno = ENOENT; 178 return (-1); 179 } 180 } 181 182 bzero(&jailst, sizeof(jailst)); 183 jailst.version = JAIL_API_VERSION; 184 jailst.path = pw->pw_dir; 185 if (res == NULL) { 186 (void)snprintf(jailhost, sizeof(jailhost), "hastctl"); 187 } else { 188 (void)snprintf(jailhost, sizeof(jailhost), "hastd: %s (%s)", 189 res->hr_name, role2str(res->hr_role)); 190 } 191 jailst.hostname = jailhost; 192 jailst.jailname = NULL; 193 jailst.ip4s = 0; 194 jailst.ip4 = NULL; 195 jailst.ip6s = 0; 196 jailst.ip6 = NULL; 197 if (jail(&jailst) >= 0) { 198 jailed = true; 199 } else { 200 jailed = false; 201 pjdlog_errno(LOG_WARNING, 202 "Unable to jail to directory to %s", pw->pw_dir); 203 if (chroot(pw->pw_dir) == -1) { 204 pjdlog_errno(LOG_ERR, 205 "Unable to change root directory to %s", 206 pw->pw_dir); 207 return (-1); 208 } 209 } 210 PJDLOG_VERIFY(chdir("/") == 0); 211 gidset[0] = pw->pw_gid; 212 if (setgroups(1, gidset) == -1) { 213 pjdlog_errno(LOG_ERR, "Unable to set groups to gid %u", 214 (unsigned int)pw->pw_gid); 215 return (-1); 216 } 217 if (setgid(pw->pw_gid) == -1) { 218 pjdlog_errno(LOG_ERR, "Unable to set gid to %u", 219 (unsigned int)pw->pw_gid); 220 return (-1); 221 } 222 if (setuid(pw->pw_uid) == -1) { 223 pjdlog_errno(LOG_ERR, "Unable to set uid to %u", 224 (unsigned int)pw->pw_uid); 225 return (-1); 226 } 227 228 #ifdef HAVE_CAPSICUM 229 capsicum = (cap_enter() == 0); 230 if (!capsicum) { 231 pjdlog_common(LOG_DEBUG, 1, errno, 232 "Unable to sandbox using capsicum"); 233 } else if (res != NULL) { 234 cap_rights_t rights; 235 static const unsigned long geomcmds[] = { 236 DIOCGDELETE, 237 DIOCGFLUSH 238 }; 239 240 PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY || 241 res->hr_role == HAST_ROLE_SECONDARY); 242 243 cap_rights_init(&rights, CAP_FLOCK, CAP_IOCTL, CAP_PREAD, 244 CAP_PWRITE); 245 if (cap_rights_limit(res->hr_localfd, &rights) == -1) { 246 pjdlog_errno(LOG_ERR, 247 "Unable to limit capability rights on local descriptor"); 248 } 249 if (cap_ioctls_limit(res->hr_localfd, geomcmds, 250 nitems(geomcmds)) == -1) { 251 pjdlog_errno(LOG_ERR, 252 "Unable to limit allowed GEOM ioctls"); 253 } 254 255 if (res->hr_role == HAST_ROLE_PRIMARY) { 256 static const unsigned long ggatecmds[] = { 257 G_GATE_CMD_MODIFY, 258 G_GATE_CMD_START, 259 G_GATE_CMD_DONE, 260 G_GATE_CMD_DESTROY 261 }; 262 263 cap_rights_init(&rights, CAP_IOCTL); 264 if (cap_rights_limit(res->hr_ggatefd, &rights) == -1) { 265 pjdlog_errno(LOG_ERR, 266 "Unable to limit capability rights to CAP_IOCTL on ggate descriptor"); 267 } 268 if (cap_ioctls_limit(res->hr_ggatefd, ggatecmds, 269 nitems(ggatecmds)) == -1) { 270 pjdlog_errno(LOG_ERR, 271 "Unable to limit allowed ggate ioctls"); 272 } 273 } 274 } 275 #else 276 capsicum = false; 277 #endif 278 279 /* 280 * Better be sure that everything succeeded. 281 */ 282 PJDLOG_VERIFY(getresuid(&ruid, &euid, &suid) == 0); 283 PJDLOG_VERIFY(ruid == pw->pw_uid); 284 PJDLOG_VERIFY(euid == pw->pw_uid); 285 PJDLOG_VERIFY(suid == pw->pw_uid); 286 PJDLOG_VERIFY(getresgid(&rgid, &egid, &sgid) == 0); 287 PJDLOG_VERIFY(rgid == pw->pw_gid); 288 PJDLOG_VERIFY(egid == pw->pw_gid); 289 PJDLOG_VERIFY(sgid == pw->pw_gid); 290 PJDLOG_VERIFY(getgroups(0, NULL) == 1); 291 PJDLOG_VERIFY(getgroups(1, gidset) == 1); 292 PJDLOG_VERIFY(gidset[0] == pw->pw_gid); 293 294 pjdlog_debug(1, 295 "Privileges successfully dropped using %s%s+setgid+setuid.", 296 capsicum ? "capsicum+" : "", jailed ? "jail" : "chroot"); 297 298 return (0); 299 } 300